Horseshoe

ABSTRACT

A horseshoe made of a single piece of metal or the like has a peripheral side surface that is inclined in substantial conformity with the hoof wall and a relatively smooth continuous bottom ground engaging surface that is concave inwardly from a relatively sharp edged intersection with the side surface.

United States Patent 72] Inventors Max B. Kirkpatrick Anchorage, Alaska (P.0. Box 1509, Wickenburg, Ariz. 85358); Andrew Harvey; John M. Sparks, Ill, P.O. Box 1509, Wickenburg, Ariz. 85358 [21] Appl. No. 781,717 [22] Filed Dec. 6, 1968 [45] Patented May 11, 1971 [54] HORSESHOE 8 Claims, 15 Drawing Figs.

[52] US. Cl 168/24, 168/4 [51] Int. Cl A0lj 01/02 [50] Field ofSearch 168/4, 24- [56] References Cited UNITED STATES PATENTS 56,888 8/1866 Bonnet 168/24 FOREIGN PATENTS 188,389 11/1922 GreatBritain Primary Examiner-Aldrich F. Medbery' Attorney--Strauch, Nolan, Neale, Nies & Kurz side surface.

ABSTRACT:- A horse/ shoe made of a single piece of metal or thelike has a peripheral "side surface that is inclined in substantial conformity with the hoof wall and a relatively smooth continuous bottom ground engaging surface that is concave inwardly from a relatively sharp edged intersection with the PATENTED um I IQYI SHEET 1 [1F 3 INVENTORS gm RV, A K PMR M .m m am W MAMW w ATTORNEYS PATENTED km 1 Ian SHEET 2 BF 3 FIG. 5

INVENTORS MAX B. KIRKPATRICK ANDREW 6. HARVEY JOHN M. SPARKS, .ZH'

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ATTORNEYS PATENTED RAH I IQII sum 30? 3 FIG. 8

MAX 8. KIRKPATRICK ANDREW 6. HARVEY JOHN M. $PARK$,.ZZI

ATTORNEYS 1 IIQRSESIIOE BACKGROUND AND SUMMARY OF THE INVENTION The invention relates to the proper shoeing of horses, particularly race horses, for maximum utilization of effortwithout causing excess strain or damage to the animal.

The horse in nature evolved as a flight animal, depending upon awareness, speed in starting and running over the available terrain and related factors to escapeinjury or death from predatory animals. During evolution the horse's legs and other members developed according to the demands for survival. The horse in nature .was of course .unshod, and in time the hoof composition and shape adapted itself .toroptimum coaction with the terrain.

The horse's hoof, so developed and as it exists today, comprises an outer hard solid wall mainly surroundingan internal .bone and connecting structure across the bottom of which extends a relatively soft sole. The heel section of thesole is called the frog and it flexes during walking and running to promote blood circulation.

The hoof wall extends at a mainly acute angle to the general plane of the sole. This angle is most acute in the sector at the front or toe of the hoof, and in the front feetit may usually vary between 45 and 60 depending on the horse. At the rear feet, the wall angle .at the front sector of .the hoof is usually about 5 smaller, providing a sharper front edge of the. hoof.

Progressing from the toe sector rearwardly, the wall is disposed substantially slightly below the sole, and'the-sole is shallowly concave downwardly'with its peripheral edges merging into the adjacent inner side of the lower edgeof the wall.

Thus, in the natural hoof of the horse, the bottom comprises a central cup-shaped concave region around the periphery of which extends the relatively sharp lower edge of a hard outer wall, and the outer surface of the wall defines atits lower edge an acute angle that is sharpest at the toe sector and may become less sharp around the quarters and at the heel.

This hoof contour enables the animal to make quick sure starts and attain and maintain running speed. It has been observed that the unshod horse in running will usually contact the ground first with the toe sectors of each hoof. The sharp hoof toe provides for easy and rapid penetration of the soil, re-

gardless of its looseness sufficiently and to a point providing an effective anchor in the harder ground about'which the hoof pivots during normal leg action. This is the natural mode of running produced by evolution.

After the horse became tamed and man started riding, the added weight and more consistent walking and :running usually resulted in sore feet. Thehorse was shod primarily to protect against shock and abrasion at the hoof. The conventional shoe was and still is a rigid generally U-shaped-metal member secured upon the bottom of thehoof wall by nails passing into and through the hoof wall.

The sport of racing horses is widespread, and considerable ingenuity has been exercised in all fields for attaining the ultimate goal of producing faster horses. The race horse atthe track today is usually required to beshod, and thus there has been considerable inquiry into the problem of the invention by experts acquainted with racing conditions. Many proposals for improvement have been offered and many areused, and inthe main most of these improvements seem to be directed into two main classes.

In one class, the usual rigid metal shoe is provided with depending projections, calks and the like intended to improve traction. For example, one of these shoes has an arcuate sharp bar known as a toe grab projecting down from the toe sector. In another, as shown in Burton U.S. Pat. No. 2,742,969, an arcuate barlike projection extends all around the'bottom of the shoe and is knife edged at the front sector intended for rapid penetration of the ground.

In the other class, attempts were made to cushion the shock of impact of the hoof with the ground. These proposals usually consisted in providing the rigid metal shoe with rubber springs or like resilient components, and some proposed flexible shoe structures.

The present invention involves a radical departure from any of the foregoing or other known proposals. vThe invention includes the basic discovery that shoes presently used on race horses and relied upon for improving traction and thrust all incorporate more or less blunt front edges and downward projections that, in addition to failing to provide improved traction, especially in starting and at high running speeds, actually have functioned to reduce speeds and rendered the home more susceptible to leg injuries.

An animal attempting his natural mode of running with these previously known shoes soon becomes aware that'impact of the bluntfront hoof edges and projections resulted in increased shock and concussion with little or no ground penetration, .with the resultthat the hooves stubbed, skidded and, failed to provide a desirable ground anchor. Footing became unstable, energy was'wasted and speed was reduced. The animal soon became aware that the shock could be reduced and some stability could be'attained only by landing and mainly, on his heels and substantially flatfooted with each footduring running. I v This radically altered the animals natural mode of running and introduced different and unnatural leg actions which are believed to be the source of manyof theleg injuries and ailments suffered by racing horses today. i

Referring to the diagrammatic illustration in FIG. 1, wherein the horse is shod with a conventional-shoe 10, also illustrated in FIG. 3,'this shows at A in position a the front leg 11f 'of ahorse directly after impact of the hoof 12 flatfooted or heel first with the relatively loose surface soil 13 of .the track, with thehorse directly over the leg and moving forwardly (to the left). The forelimbs of a horse bear about 60- --75 percent of the animals weight so that concession'is greater there. The rearlimbs provide most of the propulsive power although the forelimbs aid considerably. Observation of many horses in actual racing has shown that the average shod horse today first contacts the ground heel first or at best substantially flat footed as shown for'hoof 12 at a, probablyin an unconscious effort to prevent concussion shock due to blunt shoe impact. Such impact will produce little or no penetration of toe. grab 14 into the harder ground 15 below the loose surface dirt or mud.

The animal shod as in FIGS. 1 and 3 retains his hoof after impact substantially immovable and flat on the ground as the leg-pivots through position b andup to a further position c where finally thehoof starts to rock about the front edge.

At position 0 and d, the latter indicating the end of the thrust stroke, the turning hoof 12 may slightly penetrate further into the hardground, buy the net effect -will be a shallow scooping action wherein the front edge of the shoe effectively slides back along the harder ground surface without imparting a thrust that is effectively proportionate to the expended enery- Beside the waste of energy, this mode of running is believed to promote injury'to the horses leg because staring with essentially flat footed impact and during turning of the leg through a considerable angle with'the hoof and pasternpractically flat on the ground through leg positions a to c, the sensitive'components of the leg are subjected to excessive strains. 'Forexample, as the horse contacts the ground in position'a the resultant shock is transmitted to the forepart of the leg indicated at 16', often resulting in the injury known asshin buckling. 'Asthe leg rocks between positions a to c with the hoof substantially immovable, the main tendons at the back of the leg at 17 are unduly tensioned, often resulting in bowed tendons orlike damage. Finally the sudden release at about position c accompanied by the shallow low traction scooping of the hoof, usually upsets the running rhythm, and may result in further damage.

Essentially the same action takes place at B in FIG. 1 in the rear leg action at llr.

In contrast, as diagrammatically illustrated in FIG. 2, a horse shod in accord with the invention runs with an essentially natural leg action.

In brief in the invention, it is sought to attain and provide a hoof shape and extent that is as close as possible to natural normal, wherein the running horse '5 foot positively penetrates the ground without stubbing or skidding whereby the ground gives way to allow normal natural foot action, rather than the foot attempting to compensatively adapt itself to the ground as in FIG. 1.

Referring to FIG. 2 and the front leg 11f at A, which illustrates the horse shod according to the invention with shoes indicated at 16, also shown in FIG. 4, it will be seen that the horses hoof 12 in initial ground-engaging position a does not produce a stubbed impact but instead the acute-angled front edge sector has penetrated already through the loose dirt into the harder ground where it already provides for effectively anchoring about or adjacent this front edge during further leg action.

As the leg turns between positions a to d the acute-angled front edge of the hoof penetrates somewhat deeper, all the while rocking about and thrusting against an effective anchor region in the hard ground. As a result the shock to the shin region is minimized and the strain on the tendons is not increased above normal, the lower part of the leg between the hoof and cannon acting to supply substantially wrist action to implement forward speed.

The rear leg action at B in FIG. 2 is essentially the same, and since the main propulsive power is obtained here the increased traction and efficient energy conversion contributes to increases speed.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagrammatic view respectively showing at A and B front and rear leg action of a running horse shod with racing shoes of a type widely used in tracks prior to the invention;

FIG. 2 is a similar diagrammatic view showing leg action of a horse shod with shoes according to the invention;

FIG. 3 is a side elevation showing a horses hoof shod with a shoe having a toe grab according to known prior art;

FIG. 4 is a similar side elevation showing a horses hoof shod with a shoe according to an embodiment of the invention;

FIG. 5 is a bottom plan view of a horses hoof with a show of the invention attached;

FIG. 6 is a fragmentary side elevation partially broken away and in section showing hoof and shoe structure;

FIG. 6A is an enlarged partial section substantially at line 6A-6A of FIG. 5 showing further detail;

FIG. 7 is a fragmentary rear elevation partially broken away and in section to show hoof and shoe structure;

FIG. 7A is an enlarged partial section substantially at line 7A-7A of FIG. 5 showing further detail;

FIGS. 8 and 9 are respectively side and front elevations of a shoe according to the foregoing embodiment;

FIG. 10 is a side elevation showing a horse hoof shot! with a shoe according to a further embodiment;

FIG. 11 is a side elevation like FIG. 10 but partially broken away and sectioned to show shoe shape;

FIG. 12 is a bottom plan view of a horse hoof to which is secured a shoe of the FIGS. 10 and 11 embodiment; and

FIG. 13 is a generally perspective view showing the shoe of FIGS. 10-12 apart from the hoof.

PREFERRED EMBODIMENTS The application illustrates two different modes for attaining the invention.

Referring to FIGS. 4-9, the horse is shod with a special shoe 16 that may be of the usual U-shaped or horseshoe shape secured upon the lower edge of the hoof wall 17 as by the usual nails 18.

FIG. 5 is a bottom plan view of the hoof 12, showing the lower edge of wall 17, the white line 20 and the sole at 19. As

shown in FIGS. 6 and 7 the bottom surface 21 of the sole facing the ground is essentially concave in all directions usually merging into the white line at the inner periphery of the wall.

Shoe 16 is shaped essentially to conform the hoof to the natural unshod hoof condition without an appreciable increase in size. Shoe 16 is a single piece of cast, wrought or molded metal, steel or aluminum as desired. It has a flat planar top hoof wall-contacting surface 22, a substantially concave smooth continuous and unrelieved bottom ground-engaging surface 23 free of downward projections and an inclined outer peripheral surface 24 that slopes downwardly and outwardly from surface 22.

Peripheral surface 24 all around the hoof is sloped at substantially the same inclination as the slope of the outer surface 25 of the natural hoof wall. This angle is usually about 53 55 in the front sector of the front hoof indicated at 26 in FIG. 5 sometimes varying between 4560 depending on the horse. The angle smoothly changes, becoming less acute as it rounds both quarters, until as shown in FIG. 7, it may approach 90.

Thus surface 24 provides around the outer edge of the shoe a continuous smooth sloping surface that is effectively a continuation of the outer surface 25 of the hoof wall 17, steepest at the toe sector 26 and changing gradually in steepness as it approaches the heel.

Bottom surface 23 is an effective concave continuation of the natural sole surface 21. In practice it is most concave in the toe sector, and it usually gradually becomes less concave as it rounds the quarters and approaches the heel. In any event it is continuous and smooth, it merges into the sole and it is entirely free of downward projections inwardly of the acute-angled outer lower edge 27 formed by the intersection of surfaces 23 and 24.

In practice the hoof is prepared for shoeing by scraping off excess sole material to normalize sole surface 21 and cutting off the lower edge of wall 17 to provide a planar surface 28 adapted to seat flush with upper shoe surface 22. When the shoe is nailed in place it appears as in FIGS. 5-7.

The shoe provides little or no increase in size or change in shape as compared to the horses hoof in nature. A horse shod as above described with reference to FIGS. 4-9 will run with the natural leg action illustrated in FIG. 2.

FIGS. 1(l-l3 illustrate a further embodiment of the invention wherein the shoe 31 is somewhat different but includes the essential features of the invention.

Shoe 31 is preferably integrally made of thin bendable sheet metal and it comprises a bottom ground-engaging portion 32 and a peripheral wall-engaging portion 33.

In preparing the hoof for this shoe, after the cleaned concave sole surface 21 is formed, the lower edge of the hoof wall 17 is trimmed to present outside the white wall a continuous downwardly concave surface 34 that is an effective continuation of sole 21.

Shoe 31 is essentially custom fitted .to the trimmed hoof, with bottom portion 32 conforming in shape to bottom wall edge 34 and providing a downwardly concave ground-engaging surface 35.

Peripheral portion 33 similarly conforms in shape around wall surface 25 and in effect its outer surface 36 provides a substantial continuation of wall surface 25, changing in inclination toward the heel. Due to the slipper-type structure, shoe 31 requires only two rear nails 37 driven into the wall, as the inclined front portion secures it against separation from the front of the hoof.

Surface 36, like surface 24 in FIG. 6A, is most acute at the front sector and gradually becomes steeper as it rounds the quarters. Similarly bottom surface 35 is continuous and smooth, being most concave at the front sectorlike surface 23, and it provides a substantial continuation of the sole surface.

Surfaces 35 and 36 intersect in a continuous sharp outer edge 38 for optimum ground penetration. The action of a hoof shod as in FIGS. 10-13 is essentially the same as that of the earlier embodiment, and as illustrated in FIG. 2.

A horse shod according to the invention and running with the action shown in FIG. 2 essentially duplicates his development innat'ure. The shoes of the invention are light and compact, and they do not increase the natural hoof size or change its shape. In running naturally a horse strikes the track with his front feet which dig in and rock about the front edge anchor. The main thrust is from the rear legs which essentially vault the animal over the anchor formed by the front hoof digging in. This action is attained and enhanced in the invention.

in the invention, contrary to the tendency of some trainers to cut away hoof walls in the belief that smaller hoof sizes help speed, the maximum outer dimension of the hoof is retained and the shoe extends to the outer edge of the bottom of the wall thereby providing a larger area with better balance and distribution of forces.

We claim:

l. A horseshoe adapted to extend around the bottom edge surface of the wall of a hoof, said shoe having a transverse surface adapted for conforming closely to the contour of said bottom edge surface of the wall, a bottom ground-engaging surface that is substantially continuous, uninterrupted and free of projections, and an outer peripheral side surface that in inclined at substantially the same angle as and disposed as a substantial continuation of the outer periphery of the hoof wall, said side and bottom surfaces of the shoe intersecting in a substantially continuous acute angle outer edge region, said bottom surface of the shoe being shaped to a concave contour that is similar to the unshod naturally shaped bottom surface of the hoof within the wall and said outer edge region of the shoe simulating a natural hoof rim portion whereby during running the shod hoof may relatively cleanly penetrate the ground without blunting impact.

2. A horseshoe as defined in claim 1, wherein said side surface of the shoe is of gradually changing slope from a sector at the toe of said shoe to steeper regions toward the heel.

3. A horseshoe as defined in claim 1, wherein said concave surface curves smoothly inwardly to merge substantially into the contour of said naturally shaped sole of said hoof.

- said flat wall surface in a plane extending transversely of the hoof, and said peripheral side surface extends downwardly and outwardly from said upper surface.

5. A horseshoe as defined in claim 1, wherein said shoe comprises a bottom portion that is adapted to extend over and in full surface contact with the lower edge surface of the hoof wall and the adjacent surface of the sole and is 'inclined upwardly and inwardly from said shoe outer edge, and an inclined side portion that extends upwardly from said bottom portion in close conformity around the lower peripheral region of at least the front of the hoof wall adjacent said bottom edge surface of the wall, said continuous ground-engaging 'surface being on the bottom of said bottom portion of the shoe and said inclined outer peripheral surface being on said side portion of the shoe.

6. A horseshoe as defined in claim 5, wherein the shoe is made from a single piece of sheet metal that is bendable to the desired association with the hoof but stiff enough to resist substantial deformation when mounted on the hoof.

7. A horseshoe as defined in claim 1, which is transversely tapered between its inner and outer edge regions, said outer edge region having a thickness not greater than about onethird the width of said shoe.

8. A horseshoe as defined in claim 1, wherein said bottom ground-engaging surface of the shoe is of changing concave contour between a region around the toe where it is most concave to regions around the heel where it is less concave. 

1. A horseshoe adapted to extend around the bottom edge surface of the wall of a hoof, said shoe having a transverse surface adapted for conforming closely to the contour of said bottom edge surface of the wall, a bottom ground-engaging surface that is substantially continuous, uninterrupted and free of projections, and an outer peripheral side surface that in inclined at substantially the same angle as and disposed as a substantial continuation of the outer periphery of the hoof wall, said side and bottom surfaces of the shoe intersecting in a substantially continuous acute angle outer edge region, said bottom surface of the shoe being shaped to a concave contour that is similar to the unshod naturally shaped bottom surface of the hoof within the wall and said outer edge region of the shoe simulating a natural hoof rim portion whereby during running the shod hoof may relatively cleanly penetrate the ground without blunting impact.
 2. A horseshoe as defined in claim 1, wherein said side surface of the shoe is of gradually changing slope from a sector at the toe of said shoe to steeper regions toward the heel.
 3. A horseshoe as defined in claim 1, wherein said concave surface curves smoothly inwardly to merge substantially into the contour of said naturally shaped sole of said hoof. 4, A horseshoe as defined in claim 1, wherein said bottom edge surface of the hoof wall is flat and said transverse surface comprises a flat upper surface on said shoe adapted to engage said flat wall surface in a plane extending transversely of the hoof, and said peripheral side surface extends downwardly and outwardly from said upper surface.
 5. A horseshoe as defined in claim 1, wherein said shoe comprises a bottom portion that is adapted to extend over and in full surface contact with the lower edge surface of the hoof wall and the adjacent surface of the sole and is inclined upwardly and inwardly from said shoe outer edge, and an inclined side portion that extends upwardly from said bottom portion in close conformity around the lower peripheral region of at least the front of the hoof wall adjacent said bottom edge surface of the wall, said continuous ground-engaging surface being on the bottom of said bottom portion of the shoe and said inclined outer peripheral surface being on said side portion of the shoe.
 6. A horseshoe as defined in claim 5, wherein the shoe is made from a single piece of sheet metal that is bendable to the desired association with the hoof but stiff enough to resist substantial deformation when mounted on the hoof.
 7. A horseshoe as defined in claim 1, which is transversely tapered between its inner and outer edge regions, said outer edge region having a thickness not greater than about one-third the width of said shoe.
 8. A horseshoe as defined in claim 1, wherein said bottom ground-engaging surface of the shoe is of changing concave contour between a region around the toe where it is most concave to regions around the heel where it is less concave. 